Copper converter



April 4, 1967 c. H SCHWEINSBERG COPPER CONVERTER Filed March 16, 1964 ETAL 3,312,457

//VV/V7'0A5 CHARLES y. SC/JWEl/VSBE/PGI HARVEY .4. FREEMAN United States Patent 3,312,457 COPPER CONVERTER Charles H. Schweinsberg and Harvey A. Freeman,

Pittsburgh, Pa., assignors to Harbison-Walker Refactories Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 16, 1964, Ser. No. 352,000 4 Claims. (Cl. 26636) This invention relates to copper converters an, specifically to a novel zoned refractory lining for such as a copper converter of the Pierce-Smith type, for example.

Background The earliest copper converters, of which we are aware, which were used for refining copper, from the standpoint of structure, generally consisted of an upright steel vessel lined with silica refractories. The acid linings of these vessels had two purposes; namely (1) they protected the shell from overheating, as refractories conventionally do, and

(2) they provided some of the necessary siliceous flux for reacting with the FeO of the slag during the refining operation.

These vessels with a consumable type of siliceous acid lining were replaced in about 1905 by the Pierce-Smith converter, which employed a basic refractory lining. The Pierce-Smith vessel construction consisted of a plurality of steel panels interconnected to form a large, generally circumferential barrel. Encircling metal straps were used to reinforce the steel plates or panels. This barrel was (and still is) usually positioned so its longitudinal or long axis was parallel with the ground, or at least almost horizontal, as distinguished from upright or vertical. The Pierce-Smith converter became rather commonplace by 1909. These vessels, in modem practice, are lined with magnesia or magnesite brick (we use the term magnesia or magnesite interchangeably, but intend to describe, unless otherwise specifically stated to the contrary, a hard fired or dead burned MgO material of well-developed periclase crystal structure). Some use has been suggested of unburned magnesia-chrome ore refractories, but the severity of modern operating techniques is leading towards use of burned brick, exclusively, preferably of the chrome ore-magnesia type.

The metallurgy involved In use of the Pierce-Smith converter, that vessel is charged with molten matte from a reverberatory furnace which precedes the converter in copper refining practice. The hot matte is subjected to air blasts, which are introduced into the vessel through tuyers. The air causes oxidation of sulfides in the matte, with attendant violent exothermic reactions. The temperature of the reaction is controlled by the rate or quantity of air which is introduced to the vessel, as well as by introduction of cold or room temperature material. The preferred temperature generally is in the range 2000 to 2400 F. Detailed background of the procedure, upon which a copper converter of the Pierce-Smith type is operated, may be found in a book entitled, An Outline of Metallurgical Practice, Hayward, C. R., 1958, by D. Van Nostrand Company, Inc., New York, 3rd edition.

The composition of matte is known to those skilled in the art, and detailed explanation thereof is believed unnecessary. In essence, however, it is comprised of hot copper ore and flux. The Cu content of copper matte varies, perhaps, between 22 and 65%. The other essential ingredient, silica, ranges between and 31%. During the converting operation, in which oxygen-enriched or containing gas or air is injected into the molten or hot matte, there is chemical reaction between iron and sulfur in the matte. The reactions cause a separation of the iron into the slag as various oxides, and copper metal retention in the matte. There is evolution of sulfur, as sulfur trioxide to the furnace atmosphere. There are, of course, intermediate reaction products, in which iron combines with sulfur as iron sulfide and reacts with oxygen and with cuprous oxide to form copper sulfide and various oxide-s, etc. These reactions, just outlined, demonstrate the affinity of iron for oxygen is great enough to depress oxidation of the copper, thus allowing separation of these materials into slag and matte. The various oxides, produced in the foregoing manner, are understood to then react with the silica of the flux addition to form the terrous silica, fayalite. Strong oxidizing conditions can cause oxidation of ferrous oxide to magnetite. This/latter reaction is not desirable since the refractory oxide, magnetite, builds up when the matte is returned to the reverberatory. Magnetite accumulation can be controlled by increase in silica content.

Rerfractory alteration Basic refractory brick used in the copper converter are, of course, degraded during operation of the converter. The mechanisms of chemical attack are fairly well known. See, for example, the American Journal of Science publication, by Bowen and Schairer in Sept. 29, 1935. In general, this article and others like it teach that an increasing percentage of silica within the slag causes a general trend towards more solubility of refractory magnesia within the liquid ferrous silicate at converter operating temperatures. The solution of magnesia in ferrosilicate is not believed too great, from a weight percentage standpoint, when equilibrium conditions are maintained, but the violent character of copper converter chemical reactions make equilibrium conditions extremely unlikely to occur. Such conditionsare difiicult to conceive of in a converter, because of the constant replenishment of slag,

impingement of such slag upon refractory hot face, and j the rolling and sloshing of the slag and molten copper as the vessel is rotated to pour. It can, thus, be summarized, that magnesia, at the exposed hot face of basic refractories, is gradually taken into solution by a circulating ferrous silicate slag, with this solution reaction intensified as temperature increases.

Refractory destruction also occurs through the charging of cold ingots and scrap into the converter during operation. Also, there is a washing action of the converter reaction materials, which physically erodes as well as corrodes away refractory. There is penetration by the slag, matte, and the molten copper, particularly into joints between brick. Fayalite is one of the materials which appears to penetrate and in the absence of oxygen, fayalite reacts with magnesia, further reducing refractory lining life. The penetration of this slag, matte, and also metal into the brick and joints between them tends to open up the joints allowing still further penetration. Open fissures and cracks within the brick can also result by penetration of the interstices between particles which make up these brick. With such fissu'ring and cracking, chunks of brick hot face can fall off. Such breaking off of pieces is, of course, aided and abetted by the thermal stresses set up during cycling of the converter and due to the physical stresses resulting from rotation of the vessel during tapping.

Objects of this invention It is a primary object of this invention to provide an improved lining for copper converters, especially of the Pierce-Smith type. It is another object of this invention to provide improved zoned refractory linings for copper converters. It is yet another object of this invention to provide improved refractory linings for use in copper converters, which linings are better able to resist penetration by slag, copper metal and matte as well as exhibiting increased resistance to reaction with these materials.

The invention in brief In brief, this invention is comprised of a novel zoned copper converter structure. The structure includes the conventional barrel, ends and like structure of such as the Pierce-Smith converter. There is provided therein a novel arrangement of refractory. This arrangement includes refractory endwalls divided into three zones one of which is an intermediate zone adjacent to expected areas of slag impingement and contact. All the endwall refrac tory is burned and of the magnesia-chrome ore type. The batch from which the refractory of the intermediate zone is made further includes 1 to of very finely divided water-insoluble, high purity, green chrome sesquioxide, substantially all of the discrete particles of which are substantially uniform in size and average less than about 1 micron in diameter.

The barrel is, likewise, zoned. Adjacent one side and substantially along a horizontal axis, there is an aligned series of apertured tuyere blocks. These tuyere blocks are fabricated of material which is substantially the same as that used to fabricate the intermediate zones of the endwalls. There is an upper and a lower tuyere boundary zone. These are of the same material as the tuyere block, but are in the form of more conventional brick shapes. The total circumferential or arcuate extent of these two boundary zones and the tuyere block covers areas of expected slag contact and impingement above the tuyeres, and extends below the tuyeres to cover that area where the most violent and turbulent intermixing and reaction occurs in the slag and matte, because of the blasts of air introduced th rough the tuyeres. Preferably, an arcuate area of an opposed wall of the barrel is of the same burned chrome ore-magnesia refractory including the finely divided green chrome sesquioxide, as discussed with reference to the endwalls, tuyeres and tuyere boundary zones.

There is a bottom zone, which extends between the barrel side wall zones, and it is comprised of chrome oremagnesia burned shapes of the type used to complete the endwall. A preferred one is comprised of to magnesia and 65 to 70% chrome ore. The last zone is the upper, vapor-contacting zone, and it constitutes the remainder of the lining of the barrel.

At least all of the brick of the type which include the green chrome sesquioxide are joined together with a novel mortar. The mortar has been shown in actual tests to resist penetration and reaction with copper and copper slags more than the brick they are used to join. It substantially eliminates deep penetration and attack at the joints. It is comprised of a dry refractory batch mixed with water. The dry refractory batch consists of chrome ore and green chrome sesquioxide, the chrome ore constituting frorn to about 80 parts, by weight, and the green chrome sesquioxide from about 10 to 40 parts, by weight. It is preferable that the chrome ore be Turkish chrome ore, although others can be used. If one desires, a minor amount of magnesia may be added, as long as the Cr O to MgO oxide analysis of the total dry batch is, by weight, and on the basis of an oxide analysis greater than at least 3 to 1; but we do not recommend addition of magnesia for best results.

Other objects and further features and advantages of the invention will become apparent from the following detailed description, with reference to the appended drawings. It should be understood that the drawing and the description indicate the best mode now known to us for the practice of our invention, but that the true measure of the spirit and scope of this invention is broader than the specific examples; and we do not intend to be limited thereto but, rather, by the scope of the appended claims. In the single figure of the drawings, there is shown a side sectional view of a copper converter of the Pierce-Smith type provided with a novel zoned refractory lining according to this invention. Some auxiliary parts have been omitted for the sake of clarity and to maintain drawing simplicity.

in the drawings there is shown a tubular metal shell 1%, which serves as the barrel portion of the converter. 1 iounted about the exterior surface of the barrel, at spaced intervals, are bull gears ill. The bull gears are arranged to be driven by such as the smaller pinion gear 12, in order to rotate the vessel to allow tapping from the port 33. Metal webs 14 space the bull gears 11 from the metal skin 10.

On the right-hand side, there is shown a pair of generally ovoid conduits 15, which are the bustle or air supply for the vessel. They are interconnected with nozzles 16 by flexible conduits 17. The nozzles 16 include snout portions 18 which extend through a preformed aperture in mated pairs of tuyere blocks 19.

The ends of the barrel are closed off by refractory endwalls 29. While not shown in the drawings, this endwall refractory is supported in place by a network of steel l-beams or the like which are contiguous to the outside or cold surfaces of the en-dwalls. As is conventional, we have shown an opening 21 through an upper portion of the endwall Zil. This opening is formed by a tubular conduit mounted in place within a group of circularly laid wedge-shaped refractory brick. A gar gun is arranged to blow or shoot crushed siliceous material through the aperture 21, as desired. The gar gun can be compared to a slingshot-type device, which forcefully propels material under spring load.

We have shown a mounting block 30 having a pair of wheel supports 31 and 32. The supports 31 and 32 each carry a pair of spaced wheels or tires 33 which are journaled through plate structure 34 carried 'by the supports 31 and 32. In operation, the small gear 12 rotates on its shaft 33 under the influence of an external power source we have not shown in the drawings to, in turn, rotate the entire converter because of the contact between the pinion and the bull gear 11, on the wheels 33.

The endwall 20 is zoned. It includes an intermediate zone 40 fabricated of a burned magnesia-chrome ore brick. The brick are made from a batch consisting essentiaily of from 6080% chrome ore, such as Philippine chrome ore concentrates (having less than about 3 or 4% silica), 20 to 40 parts of magnesia (preferably of at least about 96% MgO, on an oxide basis), and green chrome sesquioxide of at least about 97% Cr O content characterized by substantially uniform particle size with practically all of the particles averaging 1 micron and less. This green chrome sesquioxide amounts to between 1 and 15%, by weight based on the total weight of the batch. The preferred brick contains 25 parts of magnesia, 65 parts of the chrome ore, both by weight; and about 10, by weight, of the batch is the green chrome sesquioxide. The brick in the zone 4% are held in place by a mortar having a Cr O content between about 40 and about and consisting essentially of low silica chrome ore and green chrome sesquioxide. Magnesia can be a batch ingredient for the mortar, but the total Cr O to MgO weight ratio of the total batch must exceed 3 to l. A preferred batch, dry solids, consists of about 60 parts, by weight, of Turkish chrome ore and about 35 parts, by weight, of green chrome sesquioxide. The chrome ore and the green chrome sesquioxide are substantially all 28 mesh. As to the chrome ore, 50 to 60% thereof rests on a 325 mesh screen. Up to 20 or 30% of the chrome ore, however, can pass a 325 mesh screen. The green chrome sesquioxide, of course, is all finer than 325 mesh. The mortar, preferably, also includes some manner of air-setting bonding system. We prefer sodium silicate, together with a minor amount of ball clay, and, perhaps, some starch, in amounts substantially as follows: sodium silicate about 7.5 parts-by weight, ball clay about 1.5 parts-by weight, cornstarch in an amount equaling about 0.1 partby weight. Total bonds amount to on the order of 5 to of the total weight of the mortar batch. This type of mortar is disclosed and claimed in the copending application entitled Mortar, Ser. No. 312,895, filed Oct. 1, 1963,- by Ben Davies and Donald 0. McCreight, now abandoned in favor of US application Ser. No. 344,179now US. Patent No. 3,028,862 This application is owned by the same assignee as the present application. The special brick, just discussed, can be made according to the teachings of United States patent application, Ser. No. 196,887, now Patent No. 3,192,058, entitled Refractories and Methods of Manufacture Therefor, by Ben Davies and Thomas W. Smoot. This latter application is also owned by a common assignee.

The remaining upper and lower portions or zones 41 and 42 of the endwall can be fabricated of almost any burned chrome ore-magnesia refractory. For example, one containing from 80 to 60 parts, by weight, of chrome ore (such as Philippine chrome ore, Philippine chrome ore concentrates, Transvaal chrome ore, Turkish chrome ore, etc.) and to 40 parts, by weight of dead burned magnesia.

The tuyere block sections 19 are made of the same refractory as the zone 40 of the endwall. We have shown a two-piece tuyere block construction in which two mating wedge-shaped pieces are placed together to form an aperture through which the tuyere nozzle snout can be extended.

The tuyere boundary zones 50 and 51 are fabricated of the same brick as the zone 40 in the endwall. These brick are joined together and to the tuyere blocks by the same mortar as used in the fabrication of the zone 40. The total extent of the zones 50 and 51 and the tuyere blocks 19 is sufficient to build that arcuate portion of the barrel lining covering the area of direct slag contact and expected slag splash impingement, as well as the area of greatest turbulence in the molten metal and matte. This latter area is below the surface of the charge in the vessel, the upper level of which has been schematically indicated by the line 52. Note the tuyeres are also below the surface. The upper area 51 is considered the slag contact area and the area of expected slag attack and impingement. Opposed to the zones 50 and 51 and the tuyeres is another arcuate sidewall zone 53. It runs the length of the barrel (as do the zones opposed), has about the same upper and lower limits as the endwall zone 40, and has a center line which is substantially parallel to the center line of the tuyeres. This zone 53 is fabricated of the same special brick and mortar as are used to fabricate zones 40, 59, and 51.

A bottom zone 54 extends between the zones 50 and 53. It is made of burned basic refractory brick of the class chrome ore-magnesia and, preferably, laid up with the special mortar, above discussed.

The remaining zone 55 can be termed the vapor or fume-contacting portion or zone of the barrel, and is fabricated of brick similar to those used to fabricate the zone 54. The special mortar is not necessary in laying up the brick in the zone 55. However, it may be used. But, for economic reasons, we suggest more conventional mortars sold for use with basic brick of the class chrome ore-magnesia.

The drawing is substantially to scale, so relative or comparative dimensions of parts are shown in the drawing. The zones 5-0 and 51 are of about the same circumferential extent. The zone 50, however, is slightly wider and extends down to about 6 or 7 brick courses above the lowermost point of the vessel when it is in the position shown in the drawings. The exposed hot face surfaces of zones 40 and 53 are about equal in vertical extent. Their upper limits are about the same as the upper limit of the zone 51, to thereby cover the area of slag contact and expected slag splash and impingement. Further, they extend downward- 1y below the slag level 52. in the expected area of greatest turbulence, induced by the blast of air coming in the tuyeres 18. We have shown about ten courses of brick below the level 52. This is exemplary only. Each vessel has some different operating characteristics, depending on length and extent of air blast, quantity of matte and the siliceous fluxes added, etc. However, as a general rule, it can be stated that the zones 53 and 40 extend only to about the expected upper level of materials to be charged to the vessel when it is in operation to cover the area of expected slag contact, splash and impingement. These zones extend below this same level 52, a number of courses sufficient substantially to cover the area of greatest turbulence induced by the tuyeres,

While we have shown a two-piece tuyere block, it should be understood they can be cast in one piece, they can be pressed in one piece with later drilling to form the tuyere opening, etc. As is also understood, the tuyeres extend substantially the entire length of the barrel in an aligned series, said aligned series being substantially parallel to the central axis of the barrel, and substantially perpendicular to the barrel endwalls.

Unconsolidated, fine ground 28-|-200 mesh), or grain (1"+ A), periclase or dead burned magnesite used to fill the area or volume 75 between the shell 10 and the major extent of the lining. It acts as an insulating back-up and, because it is unconsolidated, also allows for some lining expansion on heat up.

Installation of a zoned lining, as detailed above, decreases refractory wear and breakdown, as compared to previous conventional burned chrome ore-magnesia shapes. It provides refractory brick and joint-filling mortar of special chemistry in those areas subject to most rapid deterioration. Because of resistance to such wear and deterioration, a converter lining campaign is extended.

The special brick, having the 1 to 15%, by weight, green chrome sesquioxide of high purity, special chemistry and sizing have low porosity and high density. This special chromic oxide, further, seems to promote formation of highly refractory spinel, by reacting with magnesia during brick burning. The spinel, which is formed, had been shown in the laboratory to be one reason for the retardation of copper converter slag and metal penetration. Microscopic examination, together with spectrochemical analysis, also has indicated appreciable retardation of hot face alteration by iron silicate slags, metallic copper, copper oxides and sulfides. It appears these brick, in some manner, preferentially react with the slag to form laminated coatings containing copper oxides, spinels, and ferrosilicates over the brick working face. Stated another way, it appears that these brick, as a consequence of relative immunities to solution and reaction with the slag, form these laminated coatings. These laminated coatings prevent the washing or erosion of the brick during contact with the converter charge. Still further, it appears the chromic oxide in some manner, impedes the penetration of fayalite' slag by promoting disassociation of the fayalite into two new refractory compounds; namely, magnesium silicate and ferrous chromite. Upon disassociation and formation of these latter refractory ingredients, they solidify in situ filling up pores and grain interstices of the brick, to thereby prevent further and deeper penetration by the corrosive fayalite slag or at least inhibit the rate or degree of penetration.

As noted above, the brick used to fabricate zones 40, 50, 51 and 53 should be low in silica. This is done by using a high purity magnesite (at least about 97 or 98% MgO) and low silica chrome ore (no more than about 3 or 4% silica). It should be understood, however, that other materials having higher silicate content, can be used. In general, we suggest less than about 5% total of silica in the brick.

Another benefit of the laminated coating and pore filling, above noted, is inhibition of sulfur gas penetration.

serene? Previously, such gas could react with the magnesia of the refractory to form magnesium sulfate. There has been evidence that magnesia derived from thermal dissociation of magnesium sulfate is quite reactive with ferrous silicate slag.

The special mortar, above discussed, having a total Cr O content between 40 and 80%, etc. has been developed on many of the same theoretical considerations that were involved in the development of the special brick used for zones 40, 50, 51 and 53. It is low in silica, high in chromic oxide, with only enough binder of siliceous nature to hold these materials in place. (Of course, other binders can be used, for example, water solutions of sodium silicates, various alkaline chrome compounds, etc.) Upon the burn in encountered in service, some of the chromic oxide forms a spinel, particularly as its exposed face, which acts as a nonreactive barrier layer against infiltration of metallic copper, and the corrosive slag constituents conventionally found in copper converters. Many of the same laminated reaction product layers, discussed above, with reference to this special brick used to fabricate zones 4-1, 50, 51 and 53, also occur in the mortar. For example, the FeO content of the slag reacts with Cr O to form a refractory spinel in a siliceous glassy phase, which prevents further slag penetration.

Having thus described the invention in detail and with sufiicient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

We claim:

1. In a copper converter which includes an elongate barrel of tubular configuration extending between upright endwalls to define an enclosed refining chamber, a charging and tapping port opening through an upper portion of the barrel intermediate the ends thereof, a substantially aligned series of tuyere openings through the barrel, said series extending a major-portion of the length of the barrel and lying along an axis substantially perpendicular to the endwalls, and structure interconnected with the barrel for periodically rotating it about a longitudinal axis thereof, said barrel including a tubular outer metal skin, a zoned refractory lining disposed about the inside of said skin and extending from one endwall to the other, a portion of the lining together with adjacent metal skin defining the charging and tapping port, an inner refractory lining for said endwalls, at least an intermediate zone extending across said endwalls along a substantially horizontal axis, said zone covering the area of expected endwall slag contact, impingement with slag, and turbulence induced in a charge by air blasts from tuyeres when the vessel is in operation, zones of refractory along a side of said barrel through which the tuyeres open, said zones comprised of aligned series of tuyere blocks, an upper tuyere boundary zone and a lower tuyere boundary zone, said upper and lower boundary zones being immediately contiguous upper and lower limits of the tuyere zone and extending from one endwall to the other, a zone extending along the opposite side of the barrel opposing said series of tuyeres and upper and lower tuyere boundary zones, the arcuate extent of the said barrel side zone being sufficient to substantially cover areas of expected slag contact, slag impingement and splash, and turbulence during tuyere air blasts, a bottom barrel zone extending between respective barrel side zones, and an upper vapor contacting zone lining constituting the remainder of the lining of the tubular metal skin, all refractory shapes making up said lining beingburned chrome ore-magnesia shapes, the shapes making up the barrel side zone, upper and lower tuyere boundary zones, tuyere zone and intermediate endwall zones all being made from refractory batches which include about (1) 80-60% chrome ore, (2) 20-40% dead burned magnesia, (3) less than 5% total SiO and (4) l to by weight of very fineiy divided high purity green chrome sesquioxide substantially all the discrete particles of which are substantially equal in size and on the order of about 1 micron and less, all other burned chrome ore-magnesia shapes being made from batches which include about (1) -60% chrome ore, and (2) 20-40% magnesia, refractory mortar joining all of the refractory shapes used to make the lining for the endwalls and the barrel, the mortar used to join brick making up said barrel side zone, tuyeres, upper and lower tuyere boundary zones, and endwall intermediate zones characterized by a cr Q content, by weight on an oxide basis, between about 4-0 and 80%, from about 10 to 40%, by weight, of said Cr O content being green chrome sesquioxide of high purity, said brick making up said zones in the areas of expected turbulence, slag contact and slag impingement and splash, and the mortar used to join them characterized by surface area laminated coatings containing copper oxides, spinels, and ferrous silicates and predominantly magnesium silicate and ferrous chromite, said laminated coating substantially filling pores and grain interstices adjacent the exposed faces of the refractory whereby to restrict penetration by copper converter process materials.

2. In a copper converter which includes an elongate barrel of tubular configuration extending between upright endwalls to define an enclosed refining chamber, a charging and tapping port opening through an upper portion of the barrel intermediate the ends thereof, a substantially aligned series of tuyere openings through the barrel, said series extending a major portion of the length of the barrel and lying along an axis substantially perpendicular to the endwalls, and structure interconnected with the barrel for periodically rotating it about a longitudinal axis thereof, said barrel including a tubular outer metal skin, a zoned refractory lining disposed about the inside of said skin and extending from one endwall to the other, a portion of the lining together with adjacent metal skin defining the charging and tapping port, an inner refractory lining for said endwalls, at least an intermediate zone extending across said endwalls along a substantially horizontal axis, said zone covering the area of expected endwall slag contact, impingement with slag, and turbulence induced in a charge by air blast from tuyeres when the vessel is in operation, zones of refractory along a side of said barrel through which the tuyeres open, said zones comprised of aligned series of tuyere blocks, an upper tuyere boundary zone and a lower tuyere boundary zone, said upper and lower boundary zones being immediately contiguous upper and lower limits of the tuyere zone and extending from one endwall to the other, a zone extending along the opposite side of the barrel opposing said series of tuyeres and upper and lower tuyere boundary zones, the arcuate extent of the said barrel side zone being sufiicient to substantially cover areas of expected slag contact, slag impingement and splash, and turbulence during tuyere air blasts, a bottom barrel zone extending between respective barrel side zones, and an upper vapor contacting zone lining constituting the remainder of the lining of the tubular metal skin, all refractory shapes making up said lining being burned chrome ore-magnesia shapes, the shapes making up the barrel side zone, upper and lower tuyere boundary zones, tuyere zone and intermediate endwall zones made from refractory batches which include about (1) 80-60% chrome ore, (2) 20-40% dead burned magnesia, (3) less than 5% total SiO and (4) 1 to 15%, by weight, of very finely divided high purity green chrome sesquioxide, all other burned chrome ore-magnesia shapes being made from batches which include about (1) 80-60% chrome ore, and (2) 20-40% magnesia, refractory mortar joining all of the refractory shapes used to make the lining for the endwalls and the barrel, the mortar used to join bricks making up said barrel side zone, tuyeres, upper and lower tuyere boundary zones, and endwall intermediate zones characterized by a Cr O content, by weight on an oxide basis, between about 40 and 80%, from about 10 to 40%, by weight, of said Cr O content being green chrome sesquioxide of high purity, said brick making up said zones in the areas of expected turbulence, slag contact and slag impingement and splash, and the mortar used to join them, in operation, charac terized by surface area laminated coatings of products of reaction between the refractory brick and mortar and converter charge material, said laminated coating substantially filling pores and grain interstices adjacent the exposed faces of the refractory whereby to restrict penetration by copper converter process materials.

3. In a copper converter which includes an elongate barrel of tubular configuration extending between upright endwalls to define an enclosed refining chamber, a charging and tapping port opening through an upper portion of the barrel intermediate the ends thereof, a substantially aligned series of tuyere openings through the barrel, said series extending a major portion of the length of the barrel and lying along an axis substantially perpendicular to the endwalls, and structure interconnected with the barrel for periodically rotating it about a longitudinal axis thereof, said barrel including a tubular outer metal skin, a zoned refractory lining disposed about the inside of said skin and extending from one endwall to the other, a portion of the lining together with adjacent metal skin defining the charging and tapping port, an inner refractory lining for said endwalls, at least an intermediate zone extending across said endwalls along a substantially horizontal axis, said zone covering the area of expected endwall slag contact, impingement with slag, and turbulence induced in a charge by air blast from tuyeres when the vessel is in operation, zones of refractory along a side of said barrel through which the tuyeres open, said zones comprised of aligned series of tuyere blocks, an upper tuyere boundary zone and a lower tuyere boundary zone, said upper and lower boundary zones being immediately contiguous upper and lower limits of the tuyere zone and extending from one endwall to the other, a zone extending along the opposite side of the barrel opposing said series of tuyeres and upper and lower tuyere boundary zones, the arcuate extent of the said barrel side zone being sufiicient to substantially cover areas of expected slag contact, slag impingement and splash, and turbulence during tuyere air blasts, a bottom barrel zone extending between respective barrel side zones, and an upper vapor contacting zone lining constituting the remainder of the lining of the tubular metal skin, all refractory shapes making up said lining being burned chrome ore-magnesia shapes, the

shapes making up the barrel side zone, upper and lower tuyere boundary zones, tuyere zone and intermediate end- Wall zones all being made from refractory batches which include about (1) 80-60% chrome ore, (2) 20-40% dead burned magnesia, (3) less than 5% total SiO and (4) 1 to 15%, by Weight, of very finely divided high purity green chrome sesquioxide substantially all the discrete particles of which are substantially equal in size and on the order of about 1 micron and less, refractory mortar joining all of the refractory shapes used to make the lining for the endwalls and the barrel, the mortar used to join brick making up said barrel side zone, tuyeres, upper and lower tuyere boundary zones, and endwall intermediate zones characterized by a Cr O content, by weight on an oxide basis, between about 40 and 80%, from about 10 to 40%, by weight, of said Cr O content being green chrome sesquioxide of high purity, the remainder of the burned shapes consisting essentially of 30 to 35% magnesia and to chrome ore, said shapes making up said zones in the areas of expected turbulence, slag contact and slag impingement and splash, and the mortar used to join them characterized by surface area laminated coatings containing copper oxides, spinels, and ferrous silicates and predominantly magnesium silicate and ferrous chromite, said laminated coating substantially filling pores and grain interstices adjacent the exposed faces of the refractory whereby to restrict penetration by copper converter process materials.

4. The converter of claim 3 in which the shapes in the barrel side zone, upper and lower tuyere boundary zones, tuyere zone, and intermediate end wall zones are made from batches consisting essentially of about 25% dead burned magnesia of at least about 96% MgO, 65% chrome ore, and 10% of the green chrome sesquioxide, the total SiO content of the batch being no more than about 5%, by weight, based on the total batch weight.

References Cited by the Examiner UNITED STATES PATENTS 2,641,461 6/1953 Lewis -60 3,192,058 6/1965 Davies 106-59 3,208,862 9/1965 Davies 10660 JOHN F. CAMPBELL, Primary Examiner.

J. M. ROMANCHIK, Assistant Examiner. 

1. IN A COPPER CONVERTER WHICH INCLUDES AN ELONGATE BARREL OF TUBULAR CONFIGURATION EXTENDING BETWEEN UPRIGHT ENDWALLS TO DEFINE AN ENCLOSED REFINING CHAMBER, A CHARGING AND TAPPING PORT OPENING THROUGH AN UPPER PORTION OF THE BARREL INTERMEDIATE THE ENDS THEREOF, A SUBSTANTIALLY ALIGNED SERIES OF TUYERE OPENINGS THROUGH THE BARREL, SAID 